Tomorrow morning, SpaceX is scheduled to conduct the company’s highly anticipated first critical flight test for its Crew Dragon space capsule, known as the Pad Abort Test (PAT), at the company’s primary launch site at Cape Canaveral Air Force Station in Florida. SpaceX is already well into the development of their crewed space systems for low-Earth orbit transport, having secured a multi-billion dollar NASA contract last year to fly NASA astronauts to and from the International Space Station (ISS) starting in 2017. But before any astronaut straps themselves inside a Dragon capsule, SpaceX must successfully demonstrate the spacecraft’s ability to abort from a launch or pad emergency to safely carry crew members out of harm’s way.

Photo Credit: Mike Killian / AmericaSpace

The test is currently scheduled to take place at 9 a.m. EDT, within a 7.5-hour window available, to conduct the PAT. Should the May 6 attempt be scrubbed, SpaceX does have May 7 secured on the range to try again.

For the test, the Dragon PAT vehicle—which is a prototype of the space-worthy Crew Dragon being developed—is mounted atop a custom-made truss to simulate the spacecraft atop a Falcon-9 rocket, and it is outfitted with hundreds of instruments and sensors for data collection. An instrumented mannequin is the sole passenger, providing SpaceX with important data and other information regarding the stresses put on the mannequin—information that will be critical in ensuring development of an abort system that prevents serious injury to the crew.

A series of eight SpaceX-designed “SuperDraco” engines, an advanced version of the Draco engines currently used by SpaceX’s un-crewed “cargo only” Dragon to maneuver on orbit and during reentry, will ignite to begin the PAT—just as they would in a real emergency scenario either on the pad or in flight.

The eight SuperDraco engines are built into the side walls of the Crew Dragon and are the first fully 3-D printed engines intended for space. When lit they will produce up to 120,000 pounds of axial thrust to carry astronauts to safety (16,000 pounds of thrust each, compared to 100 pounds of thrust each with the original Draco thrusters on Dragon 1).

After ascending several thousand feet, the PAT Dragon will deploy a trio of drogue chutes, then the three main parachutes, and splash down about a mile offshore of Cape Canaveral AFS.

As noted by Ben Evans in our two-part, in-depth Dragon PAT preview, SpaceX hopes to acquire significant data in the areas of Sequencing, Closed-Loop Control, Trajectory, and External and Internal Environments. The PAT will demonstrate the proper sequencing of the pad-abort timeline, serving to validate the execution of multiple critical commands in a very short period. It will obtain trajectory data for both maximum altitude and downrange distance from the pad and will gather data on “various internal and external factors to Crew Dragon to help ensure safe conditions for crew transport.”

Interestingly, SpaceX also noted that the crash test dummy is actually not nicknamed “Buster,” despite media reports to the contrary and SpaceX Vice President of Mission Assurance Hans Koenigsmann referring to the dummy as such during last Friday’s press briefing. “Buster the Dummy already works for a great show you may have heard of, called MythBusters,” SpaceX said in a press statement Monday. “Our dummy prefers to remain anonymous for the time being.”

READ our two-part in-depth preview of the Dragon PAT and the history of abort tests that paved the way.

At 5 hours or so and counting I am predicting the toxic dragon abortion is going plunk into the ocean as planned. Pressure-fed hypergolics are so simple they are almost guaranteed to work and that lower trunk will act like a shuttlecock- which is why they are keeping it attached instead of going for a more effective escape without it.

The problem is not whether it will work- it is how dangerous all that propellent is while claiming to make it the safest spacecraft ever. As for landing back on Earth with it- I am throwing the B.S. flag on that. About as much chance of that being regular practice as making landing on the barge practical. In my view the system is intended to boost tourist space stations in orbit and this whole faux escape-landing system scheme is a facade.

The simpler (solid fuel rockets are guaranteed to work) and better system is the escape tower.

After reading your post on the inappropriateness of using hyperglolics for crewed spacecraft, I contacted a few engineers I know at NASA-JSC who have or do currently work on crewed spacecraft. I’ll let their words speak for themselves.

Hyperglolic fuel is a great option. SpaceX does use them on their crewed vehicle. You have to design your vehicle in a safe manner and that’s it. There’s nothing that stands in the way of hyperglolic fuels to be used on any safely designed spacecraft.

There is the toxicity, which could impact the crew on vehicle egress following the abort, and if rcs uses them then perhaps there would be a contamination concern during an EVA. Seems like those are case specific however and not a general rule for all human spacecraft missions. The comment against hyperglolics doesn’t sound fully true to me. “

This info from the JSC engineers pretty much agrees with a comment on this topic made a few days ago to a different article by someone else (Michael, if I recall correctly) who said he had experience working with hypergolics on the Shuttle program. Another poster (was it Joe?), who voiced safety concerns with hypergolics, specifically mentioned the potential issue of hydrazine contamination during EVAs and work he contributed to in dealing with that issue for the Shuttle program. Again, this concern is also voiced by the JSC engineers you talked to.

Multiple lines of overlapping evidence seems to support the conclusion that use of hypergolics can be safe for crewed spacecraft with proper precautions and design. Of course, if things go wrong during a landing, it could be a problem. Then again, if things go wrong with a commercial aircraft (which is carrying hundred if not thousands of gallons of combustible aviation fuel) during landing, it can be a problem as well… but I don’t see many calls for abandoning flying because of it. It just means the craft have to be properly engineered to mitigate the risks.

On the Shuttle and (hypothetically on the Orion – if Constellation Systems had not been cancelled) there were EVA “keep out zones”. The problem I mentioned involved the possible need (fortunately not required) to violate such a zone.

“There is the toxicity, which could impact the crew on vehicle egress following the abort”

Agreed Jim. But would this not also apply to a “nominal” landing of a Dragon vehicle, if the Super Drago engines are used for a powered landing?

Glad to know my memory hasn’t totally failed me. 😉 But like you mention, there is the issue of post landing hazards. It might have been you (or maybe someone else) who reminded me earlier about the technicians clad in safety gear who would have to safe the Shuttle and its propulsion system before others could approach the Shuttle or the astronauts could disembark. I assume that SpaceX has similar safety procedures developed for powered Dragon landings (and maybe contingency plans for “off nominal” landings… I assume that there were such procedures for the Shuttle as well?).

“It might have been you (or maybe someone else) who reminded me earlier about the technicians clad in safety gear who would have to safe the Shuttle and its propulsion system before others could approach the Shuttle or the astronauts could disembark.”

Guilty again.

“I assume that SpaceX has similar safety procedures developed for powered Dragon landings (and maybe contingency plans for “off nominal” landings… I assume that there were such procedures for the Shuttle as well?).”

While it doesn’t go into detail, the FAA August 2014 Final Environmental Assessment written as part of issuing the DragonFly permit includes this bit regarding landing operations:

“Post‐flight activities include DragonFly RLV landing and safing. During a nominal launch, the vehicle would land either back on the launch pad or in a predetermined targeted site within the operating area in the vicinity of launch pad. Safing activities would begin upon completion of all launch and landing activities and engine shutdown. The propellant lines would be drained into a suitable container.”

SpaceX’ abort profile has a splashdown. After the Orion splashdown, the recovery crew that secured it was wearing regular dive gear, not HAZMAT dive gear. Is a splashdown enough of a washdown that hypergolic residue isn’t a big concern, or is Orion not using hypergolics for its RCS?

For propulsive or parachute/propulsive landings on land, I can’t imagine them not needing an inspection/decontamination procedure similar to the shuttle or X-37B.

Are the retrorockets Soyuz uses for landing solid or hypergolic? Do they have any decontamination issues?

Soyuz uses solid fuel for the braking event and a hydrogen peroxide RCS system on their return capsule as far as I know. I don’t know how nasty the H202 is or if any remains in the plumbing on landing.

It is not using hypergolics for escape or landing or anything but RCS is the significant point- it has an escape tower. It carries a fraction of the amount of hypergolics that the toxic dragon does and that system is vented long before it splashes down.

That escape tower lights off and produces thrust much faster than the the pressure-fed toxic dragon. It is far more powerful at half a million pounds of thrust and only has the mass of the Orion capsule to drag – it is not dragging a trunk with it. The Orion capsule does not have landing gear and does not have 8 engines and large propellent tanks for them. KISS.

In all fairness the dragon does have the trunk to soak up explosive fragments coming at it from behind- which is very good- but it is so much slower than the Orion partly because of the mass it is a flip of the coin whether this saves it or destroys it. Orion could get perforated with fragments but because it is not carrying a ton and a half of propellents might avoid catastrophic damage to it’s own smaller propellent tanks. Orion also has a shield integral with the escape tower protecting the thin skin of the capsule (the heat shield is fairly good blast protection on the bottom of both capsules).

In my view it is not inappropriate to use this propellent combination on crewed spacecraft for in-space applications when nothing better is available. It works great for reaction control systems and is the only storable restartable combination with a decent Isp. The same engine used on the shuttle took Apollo astronauts into lunar orbit and returned them to Earth. But Apollo had an escape tower and the shuttle was based on airliner philosophy that no escape system was needed. In hindsight it was absurd to apply airliner standards to a spacecraft- and yet SpaceX is going far beyond the mistake made with the shuttle by claiming this system will be used for vertical flight. I worked on and flew on helicopters for years and all the multiple lines of evidence I am familiar with suggest landing people with this system is never going to happen. Even with a less toxic fuel load it is underpowered and has so many disadvantages compared to an escape tower risk-wise it is obvious, to me at least, that escape is secondary to why they are doing this.

Ooops. I have to apologize to Andrew LePage for misusing his comment on “multiple lines of evidence”- I thought Jim Hillhouse said that and was answering his comment. If the moderator would be so kind as to delete this remark, my 8:04 reply, and my 8:33 reply I have no problem with that- please do so.

As the tourist space station bus is getting tested it looks like we are “on track” for Mars according to Bolden. The cosmic ray rats tell a different story. And how is ARM going to help in reaching the “horizon goal”?

It is all designed to keep people from asking- why are we not going to the Moon with our Moon rocket?

I don’t like it either but I have been told to quit enough times if I did not like something to not like THAT- and unfortunately that applies here. If he really does not like it I think he can find employment elsewhere and should resign. That would actually prove he does not like it. Since the effect of not talking about the Moon on Space Exploration is ruinous and the worst thing that has ever happened to space exploration it does not matter to me if Bolden is following the boss’s orders. He is the one in charge of NASA and I am not going to commend him for being a part of keeping humankind stranded in LEO for another 40 years.

The cosmic ray rat story is probably an important benchmark in the history of spaceflight that very few people are picking up on. As SLS/Orion progresses towards actually placing human beings in a far more hazardous radiation environment than LEO there will be more on this soon.

As a troubleshooter I see clearly the flow chart on Human Space Flight-Beyond Earth and Lunar Orbit (HSF-BELO) does not have many branches. Dashing back and forth through cislunar space to and from the Moon a half dozen times almost ended in disaster due to a solar event. Few people are aware of how close we came to losing an Apollo crew to a solar storm. The sanctuary penalty for these short duration storms is bad enough but for long duration multi-year missions the seemingly impossible obstacle to overcome is cosmic radiation.

The only solution is massive shielding- and artificial gravity to address the lesser though also serious problem of zero gravity debilitation. I repeat these talking points frequently in my comments- over the last five years probably a hundred times; The mass penalty for the thousand plus tons of cosmic ray shielding and artificial gravity system means chemical propulsion is essentially useless for any HSF-BELO-capable-conveyance. Only nuclear energy will work- and to add insult to injury there is only one practical form of nuclear propulsion to be found in nuclear pulse propulsion. Atomic bombs. Actually, hydrogen bombs are the most efficient and the smaller fission devices are second best.

This inconvenient truth is so shocking to space advocates they automatically go into scornful denial. Lifting a thousand tons of tap water out of Earth’s gravity well is a non-starter. Lighting off bombs anywhere in the magnetosphere is not going to happen. Those without a simple understanding of the rocket equation and basic spaceflight principles will argue for the “flexible path” with various NewSpace propaganda slogans but these are easily refuted and then no one has a thing to say.
The silence is deafening.

While NASA publicizes LEO and Mars efforts and pushes entrepreneurial solutions any real progress in space exploration requires the anti-thesis of this policy. Abandoning the dead end of LEO, ignoring Mars for the foreseeable future, and returning to the Moon with a public works project on a never before seen scale is the only logical path.

The prophet of space colonization, Gerard K. O’Neill, figured out the Moon was the master key to open the door to space in the 70’s. What radically changed the situation even more in favor of developing the Moon was the 2010 evidence of ice deposits.

The ice on the Moon is the enabling resource that should be the central focus of all space advocacy. The only place to acquire the water-as-shielding, assemble, test, and launch nuclear missions is the Moon. It follows that the only revenue generator in space for now is the GEO satellite industry- and the only place to assemble water-shielded human-crewed space stations to supercede the present satellite junkyard is in lunar orbit using Super Heavy Lift Vehicle wet workshop upper stages. The assembled stations can transit back across cislunar space into GEO and capture the over 100 billion dollar revenues of that industry. This is the path to expanding the human presence into space- not LEO tourism. That this path bypasses LEO and is the kiss of death to the NewSpace business plan is the most inconvenient truth of all.

Just saw the video…Was that a successful test anyone?… Didn’t seem fast enough off the PAD …Are the chutes supposed to create that whiplash effect on the deployment? That looked like killer Gs…Is this how it was supposed work?

Hard to say on the speed from just the video and I’d expect the parachutes to jerk it pretty hard, but another article I’d read said splashdown was supposed to be roughly 2km from the pad. The shoreline is about 1km from the pad. It certainly didn’t look like it was anywhere near 1km offshore.

After seeing photos and video from more angles, I think the SpaceX video may have given a misleading impression that the capsule was very close to the beach, due to being shot with a long telephoto lens which has the effect of compressing the perception of depth.

Human beings can take a huge amount of G’s momentarily and survive with only slight damage- I think it is something like 40. And that is what you want in an escape system- to get away from what is happening as fast as possible. I would say it is underpowered compared to the SLS escape tower which is about half a million pounds of thrust.

Videos/films I have seen over the decades of other abort tests of various crewed capsules typically display what you called the “whiplash effect” especially when they occur at low altitudes. This and the Gs pulled during an abort (or during reentry following an abort) are among the reasons astronauts are securely strapped into form fitting couches.